Q: After parked overnight, car loses all electrical power

asked by on

The first occurrence was at approx. 20,000 and has happened two times since then. I had driven 250 miles and left my car parked overnight on the street. The next morning there was no electrical power; I even had to use the manual key because the fob would not open or close locks. I then jump-started my car and it started with no problem. When I took it to the dealership, the diagnostic found no problems and no codes. Several months after that, my car was parked overnight in a garage, same as before… next morning no electrical power… jump-started yielded complete performance. No codes, battery was tested, voltage, amps, draw test - all were okay. One month later… same as previous two times! The dealer said he had seen this before in the same make/model as mine. It had been a loose ground wire and it solved the problem for the other car. The same dealer tested my car and no problems were discovered - everything was fine. Now, we have a car that we’re afraid to drive or have our family in it. Can you offer any suggestions, advice, experience, or Anything that might help me find the cause of this?

Hello. This may sound strange, but were you parked under a street light when the battery died? I have experienced faulty florescent lights putting out RF signals (the signals that your remote fob use) that do not let the car "go to sleep" and it drains the battery.

Today’s cars have a lot of computers and they use a lot of power. The car can detect when the key fob is getting close to the car and it will wake up all the modules in the vehicle so it is ready to unlock the doors when you get to it. The RF signals from the faulty street/garage lights will make the car think that the fob is still with the vehicle and will not let the computer modules fully shut down. Unfortunately, I am not aware of any fixes for this concern other than to keep track of where it is happening and avoid those areas. I would also recommend buying a small jump pack to keep in the car so you can get the car going even if you ever experience this problem again.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. After parked overnight, car loses all electrical power

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Heater blower

If the blower motor does not respond to on and off commands at the switch, generally the switch is faulty. The turn signal issue is probably not related to the problem with the blower. If you hear the flashing unit...

Q: Service engine soon error message

If the check engine light is on (aka, "service engine soon"), that means that there is a malfunction in the engine, typically involving the engine controls such as ignition, fuel, air induction, emissions and so forth. There are thousands of...

Q: My car says the door is ajar but it really isn't

One of the more common causes of a false "door ajar" warning light is stuck contacts in the electrical switch in the door pillar. The switch can be tested. Sometimes the switch can be cleaned or serviced but that can...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.